1. Field of the Invention
An important aspect of the economics of the use of biomass as a source of fuel or of specialty chemicals is the cost involved in transporting the biomass from the location where it is produced to the location where conversion to a fuel or to specialty chemicals takes place. It is desirable to provide a process for converting biomass at or near the place of production into a pumpable liquid so it may be transported in tank cars or a pipe-line.
The present invention provides a liquid composition of biomass suspended in a liquid suspension medium, further comprising small particles of an inorganic material.
Of particular importance is that these suspensions are stable, meaning that the solid and liquid phases do not separate within the time needed to store and transport the suspensions (for example via pipe-line, rail, or road transport) to a location where they can be further processed.
It is known from the paper industry to make suspensions of cellulose fibers and inorganic materials. These suspensions do not need to be stable. To the contrary, the cellulose fibers are precipitated from the suspension and need to make inter-fiber hydrogen bonds (also referred to as paper-making bonds).
It is known from GB 2 310 865 to mix a slurry of biomass material with catalytic particles and to subject the resulting slurry to pyrolytic conditions. The slurry is processed immediately following its preparation, so there is no need for the slurry to be stable.
The composition of the present invention may be transported, for example by pipeline, or in a tank car or tank truck. The composition may also be stored in tanks. The composition is particularly suitable for use in processes whereby the biomass material is converted to liquid or gaseous fuels and/or to the valuable specialty chemicals.
In a specific embodiment the inorganic particulates also possess a catalytic functionality, meaning that the subsequent conversion of the biomass may be performed under milder conditions (lower temperature and/or lower pressure and/or shorter time) than was heretofore the case, resulting in improved products and superior process economics.
In a specific embodiment, the biomass comprises polymeric material. More specifically, the polymeric material comprises cellulose or lignocellulose. In a preferred embodiment the polymeric material comprises both cellulose and lignocellulose.
2. Description of the Related Art
Biomass is produced in large volumes in agriculture and forestry. Many of these materials are intended for use as food products for human consumption, in animal feed, or other forms of valuable materials. For example, forestry products are used as construction materials in the form of lumber, plywood, paper and paper products and paper byproducts and the like.
Incidental to the production of agricultural and forestry products, the world produces vast quantities of agricultural and forestry waste. Examples include wood chips, saw dust, straw, corn husks, bagasse, and the like. Attempts have been made to convert these waste materials to useful products. In general, these waste materials are converted to products of low intrinsic value, such as compost.
Attempts to convert these materials to products of a higher value have met with limited success. For example, conversion of agricultural waste to ethanol by fermentation is a time-consuming and expensive process. Moreover, even the most sophisticated fermentation enzymes are only able to convert at most about 50 percent of the available material. The remaining 50 percent is immune to attack by fermentation enzymes and is sometimes referred to as “recalcitrant cellulose” for this reason.
An alternative to the above approach involves converting the biomass at the location where it is produced (plantation etc) into a liquid (via pyrolysis or hydrothermal upgrading) or a gas stream (gasification) and to process these streams further in an oil or bio refinery, making optimal use of the economy of scale.
Unfortunately, transporting gas is a difficult and costly task, while most of the bio-liquids produced from biomass via thermal means are instable, in the sense that they deteriorate over time in terms of viscosity and/or chemical composition.
It is therefore an object of the present invention to provide a new liquid composition that can be made from agricultural or forestry products, or waste materials from agriculture and forestry, and that is sufficiently stable for transportation to a centralized processing location. It is a further object of the present invention to provide a biomass composition that is more easily converted to liquid or gaseous fuel or to specialty chemicals than the biomass materials from which it is derived.